Method and system for delivering fluids into a formation to promote formation breakdown

ABSTRACT

A method of delivering fluids into an underground geological formation to promote formation breakdown includes inputting, into a user interface, one or more geological formation parameters, inputting, into the user interface, one or more wellbore parameters, inputting, into the user interface, one or more fluid injection parameters, and calculating a desired breakdown pumping style based on each of the one or more geological formation parameters, one or more wellbore parameters, and one or more fluid injection parameters to promote geological formation breakdown.

BACKGROUND

Hydraulic fracturing is a process in which a geological formation is fractured by pumping a fracturing fluid at a pressure that exceeds parting pressure of the formation. The fracturing fluid is delivered into a wellbore by specially designed high pressure pumps, commonly referred to as “frac pumps”. As the frac pumps begin operation, injection rate of the fracturing fluid is maintained at the maximum matrix flow capacity causing downhole pressure to increase until a point at which the pressure exceeds a tensile strength of the geological formation. At this point, the geological formation will start to rupture and a fracture will form. The fracture will propagate in a direction ultimately perpendicular to a least principle stress presented in the formation. This process is commonly known as formation breakdown. The injection rate and outlet pressure of the frac pumps is controlled to deliver the fracturing fluid at a fluid pressure that promotes breakdown.

SUMMARY

In accordance with an exemplary embodiment, a method of delivering fluids into an underground geological formation to promote geological formation breakdown includes inputting, into a user interface, one or more geological formation parameters, inputting, into the user interface, one or more wellbore parameters, inputting, into the user interface, one or more fluid injection parameters, and calculating a desired breakdown pumping style based on each of the one or more geological formation parameters, one or more wellbore parameters, and one or more fluid injection pumping parameters.

In accordance with another aspect of an exemplary embodiment, a system includes a user interface, a memory, and a central processor unit (CPU), communicatively coupled to the memory and the user interface. The system is configured to perform a method including receiving, into the user interface, one or more geological formation parameters, receiving, into the user interface, one or more wellbore parameters, receiving, into the user interface, one or more fluid injection parameters, and calculating a desired breakdown pumping style based on each of the one or more geological formation parameters, one or more wellbore parameters, and one or more fluid injection parameters.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings wherein like elements are numbered alike in the several Figures:

FIG. 1 depicts a plurality of fracturing (frac) pumps coupled to a monitoring and control system for delivering fluids into a geological formation, in accordance with an exemplary embodiment;

FIG. 2 is a schematic representation of the monitoring and control system of FIG. 1;

FIG. 3 is a flow chart illustrating a method of delivering fluids into a formation to promote formation breakdown, in accordance with an exemplary embodiment;

FIG. 4 is a graph illustrating a first pumping pattern, in accordance with an exemplary embodiment;

FIG. 5 is a graph illustrating a second pumping pattern, in accordance with an exemplary embodiment; and

FIG. 6 is a graph illustrating a third pumping pattern, in accordance with an exemplary embodiment.

DETAILED DESCRIPTION

FIG. 1 depicts a plurality of fracturing or “frac” pumps, one of which is indicated at 2, fluidically connected to a fracturing fluid supply conduit 4. Supply conduit 4 is coupled to a manifold 6 which, in turn, is fluidically connected to a blender 8. Blender 8 combines various materials stored in fracturing tanks 10 to form a fracturing fluid mixture. Each frac pump 2 is connected to a monitoring and control system 12 for delivering fluids into a geological formation to promote formation breakdown. As shown in FIG. 2, monitoring and control system 12 includes a controller 14 having a central processor unit (CPU) 16 and a memory 18. Memory 18 includes program instructions 20 which, as will be detailed more fully below, enable system 12 to provide a breakdown pressure style for a particular formation. At this point it should be understood that the phrase “breakdown pressure style” describes a desired control of fluid injection rate and fluid treatment pressure from frac pumps 2.

Monitoring and control system 12 is further shown to include a user interface 26 and one or more sensors 30 that send data to controller 14. Controller 14 provides a breakdown pressure style output 34 desirable for a particular formation. Controller 14 also includes a breakdown pressure style adjustment output 40 that accounts for pressure changes in the particular geological formation based on inputs from sensors 30, as will be detailed more fully below. Controller 14 then controls fluid injection rate and fluid pressure through output 42 to establish and/or adjust the breakdown pressure style as will be also discussed more fully below.

Reference will now be made to FIG. 3 in describing a method 50 of determining and monitoring a geological formation breakdown style. Initially, data is input to controller 4, as shown in block 60. The data may include wellbore parameters, geological formation parameters, drilling and/or completion parameters, and/or fluid injection parameters. Examples of wellbore parameters may include inputting a wellbore depth, a wellhead pressure rating, open hole or casing configurations, and/or a wellbore deviation profile. Examples of geological formation parameters may include inputting a formation lithological type. Additional geological formation parameters may include reservoir mechanical properties including anticipated frac pressure gradient range. Examples of fluid injection parameters may include inputting a fluid type, a frac pump type, surface treating pressure, target injection rate and/or fluid rheological properties. In addition, a user may input one or more drilling/well completion parameters into controller 14. Examples of drilling and/or well completion parameters may include inputting a number of perforation clusters being treated, a number of perforations per perforation cluster, perforation intervals and/or a perforation diameter.

After receiving input data, monitoring and control system 12 outputs a recommended breakdown style, in block 62. The recommended breakdown pressure style may include a Rapid Up Breakdown style 70, as shown in FIG. 4, a Ramp Up Breakdown style 72, as shown in FIG. 5 or an Automated Step Breakdown style 74, as shown in FIG. 6. At this point it should be understood that the type and number of available breakdown styles may vary and should not be considered to be limited to the three examples shown in FIGS. 4-6. Once the breakdown pressure style is chosen and fluid injection initiated, monitoring and control system 12 monitors various pumping parameters such as, injection rate, fluid pressure, and a rate of change of pressure, in the wellbore through sensors 30, as shown in block 80.

Controller 14 compares data received from sensors 20 with stored threshold values which may be calculated by CPU 16 or manually input, that may be associated with the particular geological formation. The threshold values may include upper and lower fluid injection rate threshold values α₁ and α₂ and upper and lower injection pressure change over time or dP/dt threshold values δ₁ and δ₂. If, for example, sensed injection pressure is less than α₁ and dP/dt is less than δ₁, as determined in block 82, fluid injection rate may be increased in block 84. If for example sensed injection pressure is greater than α₁ and less than α₂ and dP/dt is greater than δ₁ and less than δ₂, as determined in block 88, fluid injection rates may be held in block 90. Further, if sensed injection pressure is greater than α₂ and dP/dt is greater than δ₂, as determined in block 94, fluid injection rate may be decreased in block 96. In this manner, monitoring and control system 12 may adjust fluid injection rate due to changes in the geological formation. Monitoring and control system 12 may also be configured to predict unfavorable conditions which may lead to job execution problems and also avoid other treatment execution issues that could lead to a less than desirable well production.

While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation. 

1. A method of delivering fluids into an underground geological formation to promote formation breakdown comprising: inputting, into a user interface, one or more geological formation parameters; inputting, into the user interface, one or more wellbore parameters; inputting, into the user interface, one or more fluid injection parameters; and calculating a desired breakdown pressure style based on each of the one or more formation parameters, one or more wellbore parameters, and one or more fluid injection parameters to promote geological formation breakdown.
 2. The method of claim 1, wherein inputting, into the user interface, one or more geological formation parameters includes inputting at least one of a geological formation lithological type and reservoir mechanical properties of the geological formation.
 3. The method of claim 1, wherein inputting, into the user interface, one or more wellbore parameters includes inputting at least one of a wellbore depth, a wellhead pressure rating, open hole configuration, casing configuration and a wellbore deviation.
 4. The method of claim 1, wherein inputting, into the user interface, one or more fluid injection parameters includes inputting at least one of a fluid type, a frac pump type, and a fluid rheological properties.
 5. The method of claim 1, further comprising: inputting, into the user interface, at least one drilling parameter and completion parameter.
 6. The method of claim 5, wherein inputting, into the user interface, at least one drilling parameter includes inputting at least one of a number of perforation clusters, a number of perforations per perforation cluster, perforation intervals and perforation diameter.
 7. The method of claim 1, further comprising: monitoring fluid injection pressure of the desired pumping pattern.
 8. The method of claim 7, further comprising: monitoring a fluid injection rate of change of the pumping pressure of the desired pumping pattern.
 9. The method of claim 8, further comprising: adjusting the rate of change of fluid injection pressure based on one of the fluid injection pressure and the rate of change of the fluid injection pressure of the desired pattern.
 10. A system comprising: a user interface; a memory; and a central processor unit (CPU), communicatively coupled to the memory and the user interface, the system configured to perform a method comprising: receiving, into the user interface, one or more formation parameters; receiving, into the user interface, one or more wellbore parameters; receiving, into the user interface, one or more fluid injection parameters; and calculating a desired breakdown pressure style based on each of the one or more formation parameters, one or more wellbore parameters, and one or more fluid injection parameters to promote geological formation breakdown.
 11. The system of claim 10, wherein receiving, into the user interface, one or more geological formation parameters includes receiving at least one of a geological formation lithological type and reservoir mechanical properties of the geological formation.
 12. The system of claim 10, wherein receiving, into the user interface, one or more wellbore parameters includes receiving at least one of a wellbore depth, a wellhead pressure rating, open hole configuration, casing configuration and a wellbore deviation.
 13. The system of claim 10, wherein receiving, into the user interface, one or more fluid injection parameters includes inputting at least one of a fluid type, a frac pump type, and a fluid rheological properties.
 14. The system of claim 10, further comprising: receiving, into the user interface, at least one drilling parameter and completion parameter.
 15. The system of claim 14, wherein receiving, into the user interface, at least one drilling parameter includes receiving at least one of a number of perforation clusters, a number of perforations per perforation cluster, perforation intervals and perforation diameter.
 16. The system of claim 10, further comprising: monitoring fluid injection pressure of the desired pumping pattern.
 17. The system of claim 16, further comprising: monitoring a rate of change of the fluid injection pressure of the desired fluid injection pattern.
 18. The system of claim 17, further comprising: adjusting the rate of change of fluid injection pressure based on one of the fluid injection pressure and the rate of change of the fluid injection pressure of the desired pattern.
 19. The system of claim 10, further comprising: introducing a breakdown fluid into a wellbore at the desired breakdown pressure style, wherein the breakdown fluid comprises a reactive fluid including one of a hydrochloric acid, blends of hydrochloric acid, hydrofluoric acid and citric acid.
 20. The system of claim 10, further comprising: introducing a breakdown fluid into a wellbore at the desired breakdown pressure style, wherein the breakdown fluid comprises a gas including one of a nitrogen gas, a nitrogen and carbon dioxide mixture, a mixture of carbon dioxide and a liquid, and a gas from a combusted propellant.
 21. The system of claim 10, further comprising: introducing a breakdown fluid into a wellbore at the desired breakdown pressure style, wherein the breakdown fluid comprises a mixture of a reactive fluid and a gas. 